(1915) Curious Result Of Hybridization (bloom times) By Dykes

For three years now I have had Iris unguicularis, or, as it is more commonly but less properly called, stylosa, in flower in the last week of September. The plants which give me these very welcome flowers are a few that resulted from crossing the typical Algerian plant with a dwarf Greek form. The interest of the cross lies in the fact that the Greek plant has never in my garden flowered until March or April.

It would be interesting to know whether any work has been done with a view to discovering the factors that determine the date at which a plant flowers. Such evidence as I have so far accumulated scarcely seems to throw any light on the question. For instance, a stray flower of Iris chamaeiris fertilised in June with pollen of Iris trojana, produced a hybrid, which is intermediate in size between its two parents and which has flowered regularly for six or eight years past in September and October. Strange to relate, however, this hybrid has refused to flower in the autumn in the south of France in a soil in which bearded Irises are far ore vigorous than they are here in this light sand. On the other hand, a cross between I. chamaeiris and the so-called I. florentina, which a neighbour raised in a garden not half a mile away, frequently gives him many spikes of white flowers in the late autumn, while in this garden it always refuses to flower except in the spring. W. B. Dykes.

For more information on historic Irises visit the Historic Iris Preservation Society at